ABSTRACT: The aim of this chapter is to provide an overview of the inter-linkages between water, energy and the environment, and the role technology can play to reduce demand and impact and increase supply. Demand, supply, and effects on the environment are the main drivers of our energy and water systems, with all three of them set to undergo significant change. Stress on water and energy resources is exacerbated by low efficiencies, for example in the agricultural sector when it concerns water use and losses in water distribution systems. Boosting water and energy use efficiency through investments in relevant technologies and infrastructure is therefore critical. To improvewater efficiencies it is important to understand the complexity ofwater treatment.The
appropriate water treatment technology will be determined by characteristics of the water sources available and quality characteristics for the discharge/re-use. It is concluded that technology alone cannot address the water and energy efficiency challenge. While water is a local issue, ensuring the allocation of sufficient supplies at the right time, in the right place, and of the right quality, sustainable water management requires increasingly consideration of the interconnectivity of larger contexts and many diverse stakeholders.